The dark underground void uncovered at a North Side construction site offered no clues as to what it held.

Geologist Philip Pearce's job was to find out, and he climbed down the steep and unstable slope using his hands to slow his descent.

What he found below the Ridge at Lookout Canyon Phase II subdivision, near the northern edge of Bexar County, was one of the most decorated caves ever discovered in the area, according to local spelunkers and cave protection associations.

The colors range from bright white and pink to dark red and brown throughout its 450-foot length.

Two chambers soar 40 feet high. Twelve-foot-long stalactites in the shape of soda straws hang from the ceiling along with sheets that look like bacon.

The floor has rounded stalagmites that rise 15 feet or more into towers resembling malformed candles.

While the cave tantalizes those who want to explore it, the developer of the 121-lot subdivision wants to seal it up and redesign around it.

The cave was discovered Jan. 30 when a crew, trenching for a sewer line, punched an opening into what was a void below ground.

To keep the public out, the property owner, McMillin Land Development, installed an 8-foot-tall chain-link fence and a half-ton, 24-inch-diameter water pipe to block the entrance.

“Basically, once the developer installs the infrastructure, it's up to SAWS to accept it, and of course we would never accept a sewer line that goes close to a (recharge) feature,” SAWS spokeswoman Anne Hayden said.

McMillin's latest proposal to the TCEQ is “to reroute the sewer lines in this area so that no sewer line will pass over or through the cave,” the developer said in a statement. “In addition, McMillin is revising the subdivision plat so that no residential lot will be over the cave.”

“We hit voids all the time,' said Gene Dawson, president of Pape-Dawson Engineers. “But rarely do we have to redesign a subdivision because of one.”

McMillin also plans to build a concrete beam across the cave entrance and then cover that in compacted earth to completely seal the entrance.

Because the developer is not using federal funds, the cave does not have to be surveyed for endangered species.

“The formations are what make it interesting,” he said, adding they are probably hundreds to thousands of years old.

He would like to see an entrance to the cave left so it could be further explored, monitored and used to teach the public how anything spilled over the recharge zone of the Edwards ends up in the aquifer.

But with the entrance sealed, Cobb knows at least the formations will be protected, until erosion, or another construction saw, breaks a new opening into the cave.